NORD gratefully acknowledges James E. Heubi, MD, Professor and Associate Chair for Clinical Research of Pediatrics, Associate Dean for Clinical and Translational Research, Children's Hospital Medical Center /University of Cincinnati College of Medicine, for assistance in the preparation of this report.
Reye syndrome is a rare disorder of childhood and adolescence. It primarily affects individuals under 18 years of age
The symptoms of Reye syndrome typically begin after a viral illness, particularly an upper respiratory infection (e.g, with influenza B virus) or, in some cases, chickenpox (varicella). Less commonly, Reye syndrome may develop after infection with other viral agents, such as influenza A or rubella. (For further information, please see the "Causes" section of this report below.)
About three to five days after the onset of viral infection, affected children experience sudden, persistent, uncontrolled vomiting. Disturbances of consciousness may begin simultaneously or develop within hours. Such abnormalities often include irritability, restlessness, disorientation, lethargy, and memory impairment. In some cases, children may remain lethargic with no progression to unconsciousness. In other cases, neurological deterioration may be rapidly progressive, leading to an apparent lack of awareness of surroundings (stupor); a state of unconsciousness and unresponsiveness (coma); widening (dilation) of the pupils (mydriasis); rapid, shallow breathing (tachypnea); a rapid heart rate (tachycardia); and loss of certain reflexes (e.g., deep tendon, pupillary, oculocephalic). Severe neurological dysfunction may also lead to episodes of uncontrolled electrical disturbances in the brain (seizures); abnormal posturing (decerebrate or decorticate rigidity), indicating damage to certain areas of the brain; and potentially life-threatening complications.
Findings associated with fatty degeneration of the liver may include enlargement of the liver (hepatomegaly) and abnormally increased levels of certain liver enzymes (hepatic transaminases), indicating impaired liver functioning. However, jaundice, a finding often associated with liver dysfunction, generally does not occur (anicteric) or is minimal in those with the disorder. Jaundice is a condition in which there is yellowish discoloration of the skin, eyes, and mucous membranes due to excessive accumulation of the pigment bilirubin in the blood.
In individuals with Reye syndrome, disease severity may be extremely variable. According to reports in the medical literature, some affected individuals may have mild symptoms without disease progression. However, as discussed above, others with the disorder may develop rapid neurological deterioration leading to potentially life-threatening complications. Researchers have proposed a clinical staging system based upon the varying levels of severity, with Grades I, II, and III indicating relatively mild to moderate disease and Grades IV and V signifying more severe disease.